Standard WP themes – 2.7+

From WP 2.7+, the way that WordPress calls the comment-list has changed, so that the code above will not work if inserted into comments.php – there has to be code added to functions.php instead, and maybe just one little tweak to the array-call in comments.php to set the avatar size. If you are using one of the WordPress framework systems, the code may need adjusting to call framework hooks instead of standard WP hooks (see next section).

Solution Source: first, add to functions.php (create it if it doesn’t already exist). This code assumes that you have uploaded your own custom gravatar image to a folder named ‘images’ in the theme directory – if you have uploaded the image elsewhere then change the code accordingly.

You should now see a new default avatar with the name you gave it in the code above added to the list (Mystery Man, Wavicon, Identicon etc) on the Settings » Discussion page. Select it as the default and save. Then there’s merely avatar size to consider, which is a simple array insertion into the comments.php file at the line where we see wp_list_comments :

<?php wp_list_comments(array('avatar_size'=>70, )); ?>

Thesis

If you are using a WordPress frameworkyou may need to alter the above code slightly to fit with the framework architecture. For Thesis you definitely need a slight change in the code. There’s a good post here but the code’s final line wasn’t quite right. A quick visit to the DIYThemes forums showed me that someone had come up with a fix: